Blind stitch sewing machine



Nov. 12, 1940.

c. w. MUELLER BLIND STITCH SEWING MACHINE Filed Nov. 15, 1958 3 Sheets-Sheet l I CharZed W fiddler.

NOV. 12, 1949 Q w MUELLER 2,221,148

BLIND STITCH SEWING MACHINE Filed Nov. 15, 1938 Sheets-Sheet 2 LkczrZeJ WMueZZer.

NOV. 12, 1940. c w MUELLER 2,221,148

BLIND STITCH SEWING MACHINE Filed Nov. 15, 1938 3 Sheets-Sheet 3 CMI'ZZJ V Mueller.

Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE BLIND STITCH SEWING MACHINE Application November 15, 1938, Serial No. 240,556

11 Claims The invention relates generally to sewing machines and primarily seeks to provide a novel machine structure of the blind stitch type capable of automatically performing roll padding operations such as are desirable in the formation of collar, lapel and similar garment portions.

In my prior Patent 1,905,391 issued April 25, 1933, I disclosed a machine of the general type referred to, and in it I disclosed means for joining superposed canvas and body fabric layers by spaced lines of stitches and for automatically bowing the canvas portions intervening lines of stitches so as to cause the attached body fabric of the lapel or similar garment portion to automatically curl or roll in the proper direction. My present invention seeks to provide certain new and useful improvements in the roll padding means previously disclosed, and to embody this improved means in a machine of the post type such as is disclosed in my prior Patent 2,038,848 issued April 28, 1936, and in my co-pending application for U. S. Letters Patent, Serial No. 127,983, filed February 26, 1937.

Among the several objects of the present invention are to provide a blind stitch sewing machine of the type stated including a stationary presser foot having a longitudinal slot therein traversed by the needle of a stitch forming mechanism and defined at its under face portion by transversely curved wall portions and end recesses; to provide a post yieldably held in spaced relation to the presser foot; to provide a work clamp composed of half sections yieldably supported on the post and conjointly formed throughout their lengths with transversely convex upper surfaces opposed to and fitting the curved wall portions and the end recesses defining the presser foot slot so as to press an arcuate rib of superposed fabric layers into the slot, and conjointly slotted and downturned at their forward ends to form guide portions and to receive and accommodate movement of an oscillatable ridge forming element; to provide a top feed dog having its under face provided with a transversely concaved, toothed groove extending throughout its length for opposing the upper convex surface of the work clamp; and to provide a stationary ridge forming element mounted on the post in front of and in aligmnent with the oscillatory ridge forming element. I

With the above and other objects in view which will more fully appear, thenatureof the invention will-be more clearly understood ,by following'the description,;theappended claims, and

the several views illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a left-side elevation of a blind stitch sewing machine embodying the invention.

Figure 2 is a front elevation of the left hand end portion of the machine illustrated in Figure 1.

Figure 3 is a detail perspective view of the'stationary presser foot looking at the under surface thereof.

Figure 4 is a. detail perspective view of the upper portion of the post and the work clamp.

Figure 5 is a fragmentary detail section illustrating a portion of the post and the work clamp.

Figure 6 is a fragmentary vertical cross section taken in the plane in which the needle oscillates, a portion of the needle being illustrated at the beginning of its stroke.

Figure '7 is a top plan view of the stationary presser foot.

Figure '8 is a detail perspective view of the feed dog,

Figure 9 is a detail perspective view illustrating the half sections of the work clamp separated.

Figure 10 is a somewhat diagrammatic cross section illustrating a fragment of body fabric and canvas secured in superposed relation, the fragment being flattened out to show how the 'bowed canvas portions intervening lines of stitches will tend automatically to hold the fabric curled or rolled.

The machine herein disclosed as embodying the invention includes a base 5, a standard 6, an overhanging arm 1 projecting laterally from the standard, and a needle arm or sewing head 8 secured to and projecting forwardly and downwardly from the free end of the arm 1.

The base includes av forward extension 9 disposed beneath the arm or head 8 and/from which rises a post receptacle I0- in which thepost I I is mounted for vertical movement in the usual manner. See for, example the illustration of the post type machine in my prior'U. S. Letters Patlent 2,038,848, issued April 28, 1936,0r in my copending applicationfor'U. S. Letters Patent SerialNo. 127,983, filed Feb. 26, 1937. The post is limited inits upward movement by a stop screw threaded type. The looper and the needle shaft are actuated from the main shaft of the machine by mechanisms (not shown) which are well known in the art and therefore not disclosed in 5 greater detail herein. Although I have specifically shown a non-threaded looper for cooperating with the needle, it is to be understood that any other complemental stitch forming mechanism may be employed. A stationary presser f-oot i8 is secured to and beneath the arm 8, as at IS, in a generally horizontal position, as illustrated in Figures 1 and 2 of the drawings. The presser foot is turned upwardly at its forward end as at and is provided at its sides with upturned mounting lugs 2| which are secured by strap brackets 22 to the arm or head 8 in the manner illustrated in Figures 1 and 2 of the drawings. The presser foot is thus rigidly supported on the arm or head 8.

The presser foot, shown in detail in Figures 3 and 7 of the drawings, includes the usual up standing grooved needle guide lug 23 and the cooperating upstanding needle support or guard sector 24. See also Figure 6. The presser foot also includes a longitudinal slotway 25 which extends in the fore-and-aft direction so as to be traversed by the oscillating needle [6. At the under surface of the foot the slot 25 is defined by concaved side walls 26 and concaved end recesses 27, the purpose for which will later be described.

A fabric ridge engaging dog 28, toothed at its rear end portion, is pivoted as at 29 on a bearing lug 36 carried by the foot and is yieldably urged into fabric ridge engaging position in the for ward end of the slotway 25 by a spring 3| coiled about the mounting pivot pin and engaged at its respective ends with the bearing lug 30 and with the dog 28, as shown in Figure 7. The dog 28 includes a stop shoulder 32 engageable with the upper surface of the foot I8 at one side of the slotway 25 so as to limit the degree to which the dog can be forced into the slotway by the spring A 4-motion top feed dog 33 is secured at 34 to an actuating arm 35 forming a part of any well known mechanism (not shown) for imparting the usual 4-motion feed movement to the dog 33.

The dog 33 is movable above and in the slotway 25, and the under surface thereof, presented for engagement with the fabric ridge projecting upwardly in the slotway, is provided with a longitudinally disposed fabric ridge engaging groove 35 which is transversely curved or concaved and is provided at each side with a row of fabric engaging teeth 31. See Figure 8.

The upper end of the post II is bifurcated to provide spaced mounting cars 38 between which is mounted a rock shaft 39 which carries a ridge forming element or disc 45. See Figures 4, 5 and 6. The ridge forming element or disc is oscillated back and forth, into and out of position for underlying the needle, and when it moves to its rearmost position, in which it closely underlies the path of travel of the needle, it projects a ridge or node of fabric into position for being penetrated by the needle in the well known manner.

The element 46 is oscillated through link and crank lever connections 4|, 42 with suitable oscillating mechanisms driven from the main shaft.

The structure and operation of these movement transmitting connections is well known, and since examples of such mechanisms are disclosed in the patents herein referred to, they are not shown in the drawings or described in detail herein.

A supporting cradle composed of spaced arms 43, mounting heads 44 and abutting mounting hubs 45, is pivoted as at 46 between the mounting ears 38 and in forward extensions 41 of these ears. See Figures 4 and 5 of the drawings. The cradle thus includes independently movable half portions, and each half portion includes a stop finger 48 which depends from the respective hub 45 and carries an adjustable stop screw 49 engageable with the post H in the manner illustrated in Figure 5 for limiting upward movement of the respective mounting head 44. A compression spring 50, socketed as at 5| in the post and engaging a centering screw 52 depending from the respective arm 43, yielding urges each mounting head 44 upwardly and holds the respective stop screw 49 in engagement with the post in the manner illustrated in Figure 5.

A work clamp opposes the stationary presser foot l8 and is designed to clamp a ridge composed of superposed fabric layers against the presser foot slotway which it opposes. The work clamp is composed of half sections 53 including fiat vertical faces or wall portions 54 which engage along the medial line of the slot in the manner illustrated in Figures 4, 6 and 7. The half sections are recessed as at 55 to compositely form a forwardly disposed ridge forming element position and movement accommodating slotway. The forward extremities of the half sections are turned downwardly to form guide ends 56, and the rear ends are similarly downturned as at 51. See Figures 4, 5 and 9.

It will be observed by reference to Figures 4 and 6 of the drawings, that the upper surfaces of the work clamp half sections are transversely convexed throughout the length of the body portions thereof, as at 58, so as to bear substantially concentric relation with, and fit into, the wall surfaces 26 and 26 which define the under surface of the presser foot slotway. See Figure 6. Each half section includes a depending mounting ear 59 which is pivotally secured as at 60 on one of the mounting heads 44, and by thus individually mounting the work clamp half sections 53 and the supporting cradle arms 43, these parts are capable of slight independent movement such as will assure perfect engagement of the work clamp in the convex presser foo-t slotway under all conditions of use.

A stationary ridge forming element 6| is supported by a suitable bracket 62 upon the post ears 38 in front of and in alignment with the oscillatable ridge forming element 40 and serves the purpose of forming a preliminary break or ridge in the composite fabric being fed into the machine over the ridge forming element 40 and the work clamp and beneath the presser foot.

In Figure 10 of the drawings, I have illustrated a fragment of superposed fabric layers comprising a body fabric 63 and a superposed canvas fragment 64. This figure illustrates the superposed fabric fragment as flattened out after having been passed through the machine and. joined by lines of stitches indicated at 65. When the composite fabric fragment is thus flattened out, the canvas 64 bows upwardly between the lines of stitches, but it is to be understood that when the fabric is relaxed, or in repose, the portions of the canvas illustrated as bowed will tend to straighten out and cause the body fabric to roll or curl.

The machine preferably includes some form of work support. In Figure 1 of the drawings this work support is indicated at 66. The work support is preferably slotted, so as to straddle the post, and mounted for swinging movement about a vertical axis 61 so that it can bemoved into and out of cooperative relation with .the post. The work support, per se, forms no part of my present invention, and the particular form of work support mentioned is disclosed in detail in my copending application for U. S. Letters Patent Serial No. 118,657, filedDec. 31, 1936.

In operation, the body fabric with a portion of canvas superposed thereon is fed. over the stationary ridge forming element BI, and then between the work clamp, composed of the half sections 53,, and the stationary presser foot l8. The stationary element BI initially breaks the superposed fabrics and forms a preliminary ridge therein, and the work clamp presses the superposed fabrics upwardly into the longitudinally concaved grooveway formed in the under surface of the presser foot. Because of the opposed relation of the convexed upper surface 58 of the work clamp and the concaved wall portions 26, 21 defining the under portion of thepresser foot grooveway 25, the superposed fabrics are pressed into a longitudinal transversely curved rib or ridge portion, and it will be observed that the arc assumed by theU-Dper or canvas layer of the superposed fabrics is greater than that assumed by the lower or body layer. Thus, when the fabric layers have been sewed together by spaced lines of stitches, the amount of canvas intervening any two adjacent lines of stitches will be greater than the amount of body fabric intervening the same two lines of stitches so that when the superposed fabrics are flattened out, as indicated in Figure 10, the surplusage of canvaswill show in the form of outwardly bowed portions. It will be obvious that when the superposed fabrics are relaxed, or in repose, the portions of the fabrics shown bowed in Figure 10 tend to straighten out and automatically impart a curl or roll .to the body fabric to which the canvas portion is attached.

The -4-motion top feed dog 33, curved at its under surface to conform to the surface of the work clamp which it opposes, feeds the superposed fabrics over the work clamp in the usual manner, and the parts are so timed that each time the needle advances to penetrate the superposed fabrics, the ridge forming element 40 will be moved rearwardly so that the rearmost or nose portion thereof will move underthe approaching needle and project a node or ridge of superposed fabrics into position-for being penetrated by the needle in the manner illustrated in Figure 6 of the drawings. 'The element 40 so positions the node of fabrics that the needle will pass completely through the canvas but only partially through the thickness of the underlying body fabric so as to cooperate with the looper I! in forming a line of single thread chain stitches in the well known manner.

The free end of the fabric ridge engaging dog 28 extends to a point adjacent the path of movement of the needle 16 and overlies the oscillating disc accommodating slotw-ay 55 in the work clamp. The dog 23 thus serves to effectively hold or clamp the fabric ridge elevatedby the element 40 during the formation of stitches therein.

It is of course to be understood that the details of structure and arrangement of parts may be variously changed and modified without departing from the spirit and scope of my invention.

'..I claim:

"1.1'In a blind stitch sewing machine, stitch forming means including a transversely oscillatable needle,.a .presser foot element,.a work clamping element, means for yieldably holding the elements in'opposed face to face relation, one of said elements having a longitudinal slot through its element opposing face defined by transversely arcuate wall -portions,.and the other of said elements including a longitudinal transversely .convexed portion for opposing and conforming with said arcuate wall portions, means for intermittently feeding superposed fabric layers longitudinally between said elements, means operable in timed relation to said needle and feed meansop- .erations to lift a node of superposed fabric layers held in transversely curved rib formation by'said elements into position for being penetrated by the needle upon each stitch forming stroke there'- of and having ineffective intervals of feed means operation, and a supplemental stationary ridge forming element mounted in front of and aligned with said node lifting means.

. 2. In a blind stitch sewing machine, stitch forming means including a transversely oscillatable needle, a wpresser footelernent, a work clamping element, means for yieldably holding the elements in opposed face to face relation, one of said elements having a longitudinal slot through its element opposing face defined by transversely arcuate wall portions, and the other of said elements including a longitudinal transversely convexed portion for opposing and conforming with said arcuate wall portions, means for intermittently feeding superposed fabric layers longitudinally between said elements, a post supporting one of said elements, an oscillatory ridge forming element supported on said post and operable in timed relation to said needle and feed means operations to lift a node of superposed fabric layers held in transversely curved rib formation by said elements into position for being penetrated by the needle upon each stitch forming stroke thereof and during ineffective intervals of feed means operation, and a stationary ridge forming elementlmounted in front of and aligned with said oscillatory ridge forming element. v

3. In a blind stitch sewing machine, stitch forming -means including. a transverselyoscillatable needle, a stationary presser foot, a post disposed beneath the foot, a work clamp supported on said post and yi eldably opposing the foot in face to face relation, said foot having a longitudinal slot therein traversed by the needle and defined at the under face of the foot 'by'transversely arcuate wall portions, and said work clamp having a longitudinal transversely convexed portion for opposing .and conforming with said wall portion-s, means for intermittently feeding superposed fabric layers. longitudinally between the foot and the clamp, and means supported on the post and operable in timed relation tosaid needle and feed means operations to lift a node of superposed fabric layers held in transversely curved rib formation by said foot and clamp into position for being penetrated by the needle upon each stitch forming stroke thereof and during ineffective intervals of feed means operation, saiolfeeding means including a feed dog operable in the foot slot and having a longitudinally grooved and toothed under surface shaped to conform to and oppose the upper transversely convex surface 0 the work clamp. I

4. In a blindstitchsewing machine, stitch forming means including a transversely oscillatable needle, a stationary presser foot, a post disposed beneath the foot, a work clamp supported on said post and yieldably opposing the foot in o face to face relation, said foot having a longitudinal slot therein traversed by the needle and defined at the under face of the foot by transversely arcuate wall portions, and said work clamp having a longitudinal'transversely con- 10 vexed portion for opposing and conforming with said wall portions, means for intermittently feeding superposed fabric layers longitudinally between the foot and the clamp, means supported on the post and operable in timed relation to said l5 needle and feed means operations to lift a node of superposed fabric layers held in transversely curved rib formation by said foot and clamp into position for being penetrated by the needle upon each stitch forming stroke thereof and during 21 ineffective intervals of feed means operation, and

a supplemental ridge forming element mounted in front of and aligned with said node lifting means.

5. In a blind stitch sewing machine, stitch forming means including a transversely oscillatable needle, a stationary presser foot, a post disposed beneath the foot, a work clamp supported on said post and yieldably opposing the foot in face to face relation, said foot having a longi- 30 tudinal slot therein traversed by the needle and defined at the underface of the foot by transversely arcuate wall portions, and said work clamp having a longitudinal transversely convexed portion for opposing and conforming with said wall 35 portions, means for intermittently feeding superposed fabric layers longitudinally between the foot and the clamp, an oscillatory ridge forming element supported on the post and operable in timed relation to said needle and feed, means 40 operations to lift a node of superposed fabric layers held in transversely curved rib formation by said foot and clamp into position for being penetrated by the needle upon each stitch forming stroke thereof and during ineffective intervals of feed means operation, and a stationary ridge forming element mounted in front of and aligned with said oscillatory ridge forming element.

6. In a blind stitch sewing machine, stitch forming means including a transversely oscillat-- able needle, a stationary presser foot, a post disposed beneath the foot, a work clamp supported on said post and yieldably opposing the foot in face to face relation, said foot having a longitudinal slot therein traversed by the needle and 55 defined at the under face of the foot by transversely arcuate wall portions, and said work clamp having a longitudinal transversely convexed portion for opposing and conforming with said wall portions, means for intermittently feeding super- 60 posed fabric layers longitudinally between the foot and the clamp, an oscillatory ridge forming element supported on the post and operable in timed relation to said needle and feed means operations to lift a node of superposed fabric layers 5 held in transversely curved rib formation by said foot and clamp into position for being penetrated by the needle upon each stitch forming stroke thereof and during ineffective intervals of feed means operation, a stationary ridge forming ele- 70 ment mounted in front of and aligned with said oscillatory ridge forming element, said clamp having .a longitudinal slotway therein extending forwardly from a point slightly in rear of the plane in which the needle oscillates and in which 75'said ridge forming element oscillates, and means overlying the foot slot just in front of the plane in which the needle oscillates for yieldably opposing the oscillatory ridge forming element and gripping fabrics passing thereover.

7. In a blind stitch sewing machine, stitch 5 forming means including a transversely oscillatable needle, a stationary presser foot, a post disposed beneath the foot, a work clamp supported on said post and yieldably opposing the foot in face to face relation, said foot having a longil0 tudinal slot therein traversed by the needle and defined at the under face of the foot by transversely arcuate wall portions, and said work clamp having a longitudinal transversely convexed portion for opposing and conforming with said Wall portions, means for intermittently feeding superposed fabric layers longitudinally between the foot and the clamp, an oscillatory ridge forming element supported on the post and operable in timed relation to said needle and feed means operations to lift a node of superposed fabric layers held in transversely curved rib formation by said foot and clamp into position for being penetrated by the needle upon each stitch forming stroke thereof and during ineffective intervals of feed means operation, and said clamp having a longitudinal slotway therein extending forwardly from a point slightly in rear of the plane in which the needle oscillates and in which said ridge forming element oscillates, and means overlying the foot. slot just in front of the plane in which the needle oscillates for yieldably opposing the oscillatory ridge forming element and gripping fabrics passing thereover.

8. In a blind stitch sewing machine, stitch forming means including a transversely oscillatable needle, a stationary presser foot, a post disposed beneath the foot, a work clamp supported on said post and yieldably opposing the foot in face to face relation, said foot having a longitudinal slot therein traversed by the needle and de fined at the under face of the foot by transversely arcuate wall portions, and said work clamp having a longitudinal transversely convexed portion for opposing and conforming with said wall 5 portions, and said work clamp being composed of half sections opposed in face to face contact along the center of the slot and each supported for independent rocking movement in the fore-and-aft direction on said post, means for intermittently feeding superposed fabric layers longitudinally between the foot and the clamp, and means supported on the post and operable in timed relation to said needle and feed means operations to lift a node of superposed fabric layers held in transversely curved rib formation by said foot and clamp into position for being penetrated by the needle upon each stitch forming stroke thereof and during ineffective intervals of feed means operation.

9. In a blind stitch sewing machine wherein is provided a reciprocating needle and a ridge forming element for presenting a node of fabric in position for being penetrated by the needle, a supplemental ridge forming element supported in 5 front of and in alignment with the first mentioned ridge forming element.

10. In a blind stitch sewing machine, the combination of an oscillatory needle, an oscillatory ridge forming element for intermittently presenting a node of fabric in position for being penetrated by the needle, and a stationary ridge forming element supported in front of and in alignbinaticn of an oscillatory needle, an oscillatory ridge forming element for intermittently presenting a node of fabric in position for being penetrated by the needle, a stationary ridge forming element supported in front of and in alignment with the oscillatory ridge forming element, and

means including respectively concaved and convexed opposing presser foot and work clamp portions for holding superposed fabrics in concentrically bowed relation-while they are being assembled by stitching.

CHARLES W. MUELLER. 

